1. Field of the Invention
This invention relates to antennas such as microstrip antennas. More specifically, the invention is an antenna having a dielectric having a geometric pattern.
2. Description of the Related Art
Fractal antennas utilize self-similar designed conductors to maximize antenna length or increase the perimeter of material that can receive or transit electromagnetic signals. Fractal antennas are compact, are multi-band or wideband, and are useful in cellular communication applications and microwave applications. The key aspect of these antennas is their fractal-pattern repetition of the antenna's conductor over two or more scale sizes or iterations. Fractal antenna performance can currently be controlled only via manipulation of the antenna conductors' fractal geometry.
3. Summary of the Invention
Accordingly, it is an object of the present invention to provide an antenna design offering improved performance, by having a dielectric layer comprising at least two dielectric materials arranged in a geometric pattern, including but not limited to, a fractal pattern.
Another object of the present invention is to provide a fractal antenna design having versatile performance manipulation capabilities.
In yet another embodiment of the present invention, an antenna comprises a ground plane, a dielectric member, and an electrically-conductive radiator disposed on the dielectric member. The antenna may further include a radome disposed on the radiator, where the radome includes at least one geometric pattern. The dielectric member may be disposed on the ground plane and include at least one layer of a first dielectric material and a second dielectric material. The first dielectric material and second dielectric material may be arranged to collectively define a dielectric geometric pattern, including but not limited to, a dielectric fractal pattern. The dielectric member may further include a layer of a third dielectric material adjacent to the at least one layer. The first dielectric material is characterized by a relative permittivity that is at least twice that of the second dielectric material. The first dielectric material and the second dielectric material are further characterized by a loss quantity that yields an antenna efficiency of at least approximately 70 percent. In one embodiment, the loss quantity does not exceed approximately 0.001. The radiator may define a radiator geometric pattern, including a radiator fractal pattern, and the radiator geometric or fractal pattern may be geometrically matched to the dielectric geometric or fractal patterns. The geometric pattern can extend fully or partially through the at least one layer. The radiator has a radiator impedance and the dielectric member has a dielectric impedance, and the radiator impedance may be substantially equal or equal to the dielectric impedance. The impedance of the radiator may be matched to the dielectric member.
In another embodiment of the present invention, a dielectric antenna comprises a ground plane, a dielectric layer and an electrically-conductive radiator disposed on the dielectric layer. The dielectric layer may be disposed on the ground plane and include a first dielectric material and a second dielectric material that collectively defines a dielectric geometric pattern, or fractal pattern, that extends fully through the dielectric layer. The first dielectric material is characterized by a relative permittivity that is at least twice that of the second dielectric material. The first dielectric material and the second dielectric material are further characterized by a loss quantity that yields an antenna efficiency of at least approximately 70 percent. The radiator defines a radiator geometric pattern, which may comprise a fractal pattern, and the radiator geometric pattern geometrically matches the dielectric geometric pattern (or fractal pattern). The radiator also has a radiator impedance and the dielectric layer has a dielectric impedance, and the radiator impedance is substantially equal or equal to the dielectric impedance. The antenna further comprises a radome disposed on the radiator. The loss quantity does not exceed approximately 0.001.
In a further embodiment, a microstrip antenna comprises a ground plane, a dielectric layer and an electrically-conductive radiator disposed on the dielectric layer and adapted to be exposed to a free space environment. The dielectric layer is disposed on the ground plane and includes a first layer of a first dielectric material and a second dielectric material. The first dielectric material and second dielectric material are arranged to define a dielectric geometric pattern, which may comprise a fractal geometry. The first dielectric material is characterized by a relative permittivity that is at least twice that of the second dielectric material. The first dielectric material and the second dielectric material are further characterized by a loss quantity that yields an antenna efficiency of at least approximately 70 percent. The conductor is impedance matched to the dielectric layer. The dielectric geometric pattern, or fractal pattern, can extend completely through the at least one layer. The loss quantity does not exceed approximately 0.001. The dielectric layer optionally includes a third dielectric material, wherein the first, second and third dielectric materials are arranged to define a dielectric geometric pattern, or a fractal pattern. Alternatively, the third dielectric material may comprise a second layer adjacent to the first layer, which is homogenous and may or may not comprise a geometric or fractal pattern.